Method for treating conductors



July 28, 1925. 1,547,363

- A. A. CATLIN ET AL METHOD FOR TREATING CONDUCTORS Filed 001:. 51., 1919 WWW Patented July 28, 1925.

UNITED STATES PATENT OFFICE.

ARTHUR A. CATLIN, OF EAST ORANGE, NEW JERSEY, AND HENRY R. MASSINGHAM,

OF OICERO', ILLINOIS, ASSIGNORS T WESTERN ELECTRIC COMPANY, INCORPO- I RATED, OF NEW YORK, N. 'Y., A CORPORATION OF NEW YORK.

METHOD FOR TREATING CONDUCTORS.

Application filed October 31, 1919'. Serial No. 334,852.

To all whom it may concern:

Be it known that we, ARTHUR A. CATLIN and HENRY R.-MAssrNc1-IAM, citizens of the United States, residing at East Orange, in

the county of Essex and State of New Jersey, and at Cicero, in the county of Cook and State of Illinois, respectively, have invented certain new and useful Improvements in Methods for Treatin Conductors, of which the following is a ful clear, concise, and exact description. I

This invention relates to flexible conductors and more particularly to a method for treating flexible insulated conductors toinsure greater life in service. In connection with flexible conductors, such as used, for example, in telephone switchboards for interconnecting the various lines, it is necessary that the outer braiding be capable of withstanding severe service in order that a satisfactory life may be obtained from the cords.-

Moreover, the ends of these cords to which the connecting plugs are attached are subjected to particularly severe treatment due to the sharp bending of the cord at this point and also due to the perspiration from the hands of the operator. It has been proposed to treat such cords by dipping them in various types of wax in order to prevent moisture from entering the conductors and thereby decreasing the insulating resistance.

Cords so treated are not only sticky and stiff but the saturation of the braiding with the impregnating compound lowers the tenthereby decreasing rather than increasing the life of the cord.

It is therefore the object of the present invention to provide a method for treating flexible conductors, whereby the outer braiding of 'the conductor is impregnated an amount suflicient to insure increased life of the covering without making the conductor stiff or sticky.

A further object is to impregnate the outer covering an amount suflicient to provide a lubrication for the various threads as they rub against each other without saturating these threads to such an extent as to impair their tensile strength.

To accomplish these objects and in ac cordance with a feature of this invention, there is provided a method of impregnating flexible conductors in which the impregnat sile strength of the threads of the braiding,

ing compound only penetrates the outer portion of the textile covering of the conductor, and in which the time of impregnation and the temperature of the compound are such as to preclude the possibility of the threads bemg saturated to such a point as to impair their tensile strength.

This and other features of the invention may be more clearly understood by referring to the attached drawings, in which Fig. 1 discloses a switchboardcord of a type which may be preferably treated in accordance with the method embodying this invention and having a portion of the braiding cut away to more clearly show its construction; Fig. 2 discloses apparatus satisfactory for performing the invention; and Fig. 3 is a view of the die forming a portion of the apparatus disclosed in Fig. 2. The typeof cord illustrated in the drawng comprises a core consisting of a plurality of insulated conductors 5-5 twisted together and provided with fillers 66 laid as shown to insure a more even core. These conductors are prevented from untwisting by means of a wrapping 7 of tape or thread wound about the core in the opposite direction to that in which the conductors are twisted. The conductors terminate at one end in a switchboard plug 8 and the core at this end is provided with a double covering consisting of an outer braiding 9 and an inner braiding 10.

The apparatus disclosed in Fig.2 comprises a metal tank 11 provided with heating means, such for example as a gas burner 12. Securely fastened to the tank 11 is a hinged die 13, the jaws of which are normally held open by means of the spring 14:. However, a foot pedal 15 is provided as shown to draw the jaws together against the tension of spring 14. The tank 11 contains the insulating compound with which it is desired to impregnate the plug end of the cord, this compound consisting preferably of' equal parts of beeswax and parafiine. By means of the gas flame 12, the temperature of this insulating compound is maintained between F. and 200 F. In

performing the method embodying this invention, the plug end of a cord such as is disclosed in Fig. 1 is immersed in the insulating compound for a period of from 2 to 4 seconds and is then immediately placed which will permit it to efficiently remove the excess compound.

By following the process outlined, the insulating compound impregnates the outer braiding 9 but does not penetrate into the 4 core of the cord. The threads of braiding 9, however, are not saturated with the insulating compound to such an extent as to impair their tensile strength but the outer surface of these individual threads is impregnated an amount suflicient to provide lubrication for the fibers as they are rubbed one over the other upon bending of the cord and also to afford protection against moisture or perspiration entering the cord to affect the insulation resistance of the conductors. By immediately removing all excess wax from the cord following its imof treating described.

mersion, the cord is prevented from becoming sticky and thus disagreeable to handle. If the insulating compound is allowed to penetrate into the core, the cord becomes too stifi to be handledv satisfactorily, a difiiculty which is overcome by following the method What is claimed is:

1; The processof treating a flexible conductor composed of a conducting core to which have been applied an inner and an outer layer of fibrous material, which consists in immersing the conductor in insulatmg compound, the temperature of the compound and the time of immersion being such that the fibrous material of the outer layer will receive a coating of the insulating com: pound but will not be saturated to such a degree as to impair its tensile strength, and then immediately removing the excess compound from the outer surface of the outer layer of fibrous material. a

2. The process of treating a flexible con ductor which consists in applyin thereto an inner and an outer layer of fi rous insulating material, immersing for a period of from two to four seconds in an insulating compound consistin of equal parts of beeswax and paraffine, t e temperature of which is not less than 180 F. nor more than 200 F., and then immediately passing through a die to remove excess compound from the Outer layer of fibrous material.

3. The process of treating a flexible conductor composed of a conducting core to which have been applied an outer and an inner layer of fibrous material, which consists in immersing the conductor in an insulatlng compound, the temperature of which is maintained between 180 200 F., for a period-of time such that the and insulating compound will impregnate the outer layer without saturating the fibrous material to such a degree as to impair its tensile strength and without penetrating the core, and then passing the conductor through a heated die to remove excess compound from the outer layer of fibrous material..

[In witness whereof, we have hereunto subscribed our names.

ARTHUR A. GATLIN. HENRY R. MASSINGHAM. 

